Response of flower and boll development to climatic factors in Egyptian cotton (Gossypium barbadense)

Fruiting of cotton plant is determined and influenced by cultivars, climatic conditions, management practices and pests. An understanding of the flowering and boll retention patterns of cotton cultivars can contribute to more efficient and economical crop management. The objective of this investigation was to study the effect of various climatic factors on flower and boll production, and also, the nature of its effects prevailing prior and subsequent to either flowering or boll setting on flower and boll production and retention in Egyptian cotton. This could be used in formulating advanced prediction of the effect of certain climatic conditions on the production of Egyptian cotton. Also, the study focused on four equal periods during the development of flower and bolls stage to study the response of these characters to climatic factors during these periods and to determine the most representative period corresponding to the overall crop pattern. Further, the study predicting effects of climatic factors during convenient intervals (in days) on cotton flower and boll production compared with daily observations to find the optimum interval. Evaporation, sunshine duration, humidity, surface soil temperature at 1800 h, and maximum air temperature, are the important climatic factors that significantly affects flower and boll production. Evaporation; minimum humidity and sunshine duration were the most effective climatic factors during preceding and succeeding periods on boll production and retention. There was a negative correlation between flower and boll production and either evaporation or sunshine duration, while that correlation with minimum humidity was positive. The fourth quarter period of the production stage was the most appropriate and usable time to collect data for determining efficient prediction equations for cotton production. Evaporation, humidity and temperature were the principal climatic factors that governed cotton flower and boll production during the fourth quarter. The five day interval was found to be adequately and sensibly related to yield parameters than other intervals and was closest to the daily observations. Evaporation was found to be the most important climatic variable affecting flower and boll production, followed by humidity. An accurate weather forecast 5–7 days in advance would provide an opportunity to avoid adverse effects of climatic factors on cotton production through utilizing proper cultural practices which would limit and control their negative effects.     

Aroma types of flue-cured tobacco in China: spatial distribution and association with climatic factors

Aroma types of flue-cured tobacco (FCT) are classified into light, medium, and heavy in China. However, the spatial distribution of FCT aroma types and the relationships among aroma types, chemical parameters, and climatic variables were still unknown at national scale. In the current study, multi-year averaged chemical parameters (total sugars, reducing sugars, nicotine, total nitrogen, chloride, and K₂O) of FCT samples with grade of C3F and climatic variables (mean, minimum and maximum temperatures, rainfall, relative humidity, and sunshine hours) during the growth periods were collected from main planting areas across China. Significant relationships were found between chemical parameters and climatic variables (p?<?0.05). A spatial distribution map of FCT aroma types were produced using support vector machine algorithms and chemical parameters. Significant differences in chemical parameters and climatic variables were observed among the three aroma types based on one-way analysis of variance (p?<?0.05). Areas with light aroma type had significantly lower values of mean, maximum, and minimum temperatures than regions with medium and heavy aroma types (p?<?0.05). Areas with heavy aroma type had significantly lower values of rainfall and relative humidity and higher values of sunshine hours than regions with light and medium aroma types (p?<?0.05). The output produced by classification and regression trees showed that sunshine hours, rainfall, and maximum temperature were the most important factors affecting FCT aroma types at national scale.     

西藏近35年地表湿润指数变化特征及其影响因素

利用1971-2005年西藏25个气象站月平均最高气温、最低气温、风速、相对湿度、日照时数、降水量等资料,应用Penman-Monteith模犁计算了最大潜在蒸散、地表湿润指数,分析了其空间分布、年际变化特征及季节差异,并讨论了影响地表湿润指数变化的气象因子.研究表明:近35年,西藏年降水量表现为显著的增加趋势,增幅为15.0 mm/(10 a);年最大潜在蒸散呈不同程度的减小趋势,为-4.6--71.6 mm/(10 a).阿里地区西南部、聂拉木年地表湿润指数为不显著的减小趋势,其他各地均呈增大趋势,增幅为0.02-0.09.就西藏平均而言,年地表湿润指数以0.04/10 a的速率显著增大,尤其足近25年增幅更为明显.各季节地表湿润指数也表现为增大趋势,以夏季增幅最明显.20世纪70年代剑80年代主要表现为以低温低湿为主的年际变化特征,进入90年代后,气温持续升高,地表湿润指数明显增加,呈现山暖湿型的气候特征.降水量和相对湿度的明显增加,以及平均气温日较差的显著减小是地表湿润指数显著增加的主要原因,平均风速和日照时数的明显减少,在湿润指数增加趋势中也起着重要作用.     

黑龙江省草地螟第三暴发周期气候特征及风险概率

1996年以来,黑龙江省草地螟第三暴发周期持续至今,危害日益加重。以1959—2008年黑龙江省28个国家基本站气象资料以及草地螟暴发期等资料为基础,分析了黑龙江省草地第三暴发周期的气候特征及风险概率。结果表明：近50 a来,黑龙江省年平均气温、年平均最低气温呈显著的上升趋势,通过0.001显著性检验,气温在1988年前后出现突变。其他要素如降水量、降水日数、风速和日照时数均呈减少趋势,但只有年日照时数和年平均风速的减少趋势通过了显著性检验。哈尔滨草地螟始发日期与同期平均气温、日最高气温、最低气温、最小相对湿度关系密切,本地越冬虫源春季羽化对气温、相对湿度敏感性较高;同时,始见日期与最大风速的风向相关较为密切,可能是由于外地虫源对风向敏感性较高。通过对黑龙江省草地螟高峰期首日的风险概率分析,得出草地螟高峰期出现在5月最后一个候的风险概率为23.6%;出现在6月上旬的风险概率为36.6%;出现在6月中旬的风险概率为24.0%;出现在6月下旬的风险概率为14.4%。     

Spatiotemporal variability of reference evapotranspiration and its contributing climatic factors in Yunnan Province, SW China, 1961–2004

Evapotranspiration is an important flux term in the water cycle that integrates atmospheric demand and surface conditions. Using the FAO Penman–Monteith method, we calculated monthly reference evapotranspiration (ET0) for 119 stations during 1961–2004 over Yunnan Province (YP), southwest China. Linear trend analysis shows that area-averaged annual and seasonal ET0 rates declined, with most remarkable decreases during pre-monsoon (?1.5 mm decade^?1, Mar–May) and monsoon (?0.6 mm decade^?1, Jun–Aug) seasons. Most of the stations with negative trends were concentrated in the eastern and northern parts of YP. Over the 44–year period, wind speed (WS), relative sunshine duration (SD) and relative humidity (RH) all showed decreasing trends, whereas maximum temperature (TMX) increased slightly. Multivariate regression analysis indicated that the variability of ET0 rates is most sensitive to the variations of SD, followed by RH, TMX and WS. The temporal evolution of these contributing factors was not stable during the study period, with an increasing contribution of SD and a decreasing contribution of TMX after the 1970s. Temporally changing contributions of climatic variables to ET0 should be taken into account when evapotranspiration rates are calculated with equations that rely on parameterization of climatic variables. Linking the changing contributions of climatic variables to ET0 rates to circulation features may help to better understand how ET0 responds to regional climatic change.     

Climate change effects on tropical night days in Seoul, Korea

In Seoul (37.57°N, 126.97°E), South Korea (located at mid-latitudes), the frequency of tropical night (TN) days, which have been defined as days with a minimum temperature greater than 25°C, have shown an increase due to the effects of temperature and water vapor. It was found that TN days accounted for almost 10.2% (July) and 22.1% (August) of the total number of days in respective months during the last decade in Seoul, and these figures may be increasing with climatic change. The daytime and nighttime sky on TN days can contain water vapor when the monsoonal southwesterly flow prevails. This strong wind may induce moisture advection from the warm ocean, and consequently, there is much larger specific humidity over the city during TN days in comparison to non-TN days. The effect of climatic change on the specific humidity is related to an increase in the number of TN days, which has shown an upward trend of 13-day/100-year and is significantly modulated by both water vapor and air temperature during July and August. Moreover, the relative role of water vapor in increasing the frequency of TN days has become much more significant after the 1960s in comparison to that of air temperature, which may be attributed to urbanization in Seoul since the 1960s.     

2002-2008年黑龙江省杨树烂皮病与气象条件的研究

分析杨树烂皮病发生发展与气象条件的相关关系,可为杨树烂皮病预报、防治提供科学依据。基于2002-2008年黑龙江省14个代表站点杨树烂皮病资料和气象资料,利用相关分析法,研究黑龙江省杨树烂皮病发生发展与气象条件的关系。结果表明：黑龙江省杨树烂皮病发病率与上年10月至当年4月平均气温、5-9月温湿系数、降水量、降水日数、上年10月和当年3月空气相对湿度、极端最高气温、气温日较差、气温日较差大的天气条件持续时间及平均风速呈正比,与上年10月至当年4月温湿系数、5-9月平均气温、上年12月至当年1月空气相对湿度、极端最低气温及日照时数呈反比。湿润、温凉和冬季冷热骤变的气候环境可加剧杨树烂皮病的发生发展,日照充足和夏季高温对杨树烂皮病有抑制作用。     

Trends, stability and stress in the Colombian Central Andes

Mountain ecosystems have been projected to experience faster rates of warming than surrounding lowlands. These changes in climatic conditions could have significant impacts on high-altitude Andean environments, affecting the quality and magnitude of their economic and environmental services. Even though long-term data in these regions are limited, it is important to identify any discernible long-term trends in local climatic conditions. Time series of several variables were analyzed to detect statistically significant long-term linear trends that occurred over recent years in a páramo ecosystem of the Colombian Central Andes. Records included cloud characteristics, sunshine, rainfall, minimum and maximum temperatures, diurnal temperature range, and relative humidity. Conditions of atmospheric stability were also explored. Total sunshine exhibited decreasing trends ranging from ?3.7 to ?8.5% per decade at altitudes around the pluviometric optimum. The strongest changes in sunshine occurred during the December-January-February season. Mean relative humidity observed at altitudes around and below this threshold showed increasing trends of +0.6 to +0.7% per decade. Annual rainfall and mean relative humidity above the optimum showed decreasing trends ranging from ?7 to ?11% per decade and from ?1.5 to ?3.6% per decade, respectively. Minimum temperatures on the coldest days and maximum temperatures on the warmest days exhibited increasing trends at all altitudes ranging from +0.1 to +0.6, and from +0.2 to +1.1°C per decade, respectively. Increases in minimum and maximum temperatures at higher altitudes were significantly greater than those observed in average at lower altitudes. The strongest changes in minimum temperatures, particularly, occurred during the December–January–February and June–July–August dry seasons. All these changes suggest that atmospheric conditions in the area are shifting from statically unstable conditions to conditionally unstable or statically stable conditions. Observed historical trends indicate that climate impacts and other human activities have stressed these unique and fragile environments.     

Evaluation of support vector machine for estimation of solar radiation from measured meteorological variables

Solar radiation is an essential and important variable to many models. However, it is measured at a very limited number of meteorological stations in the world. Developing method for accurate estimation of solar radiation from measured meteorological variables has been a focus and challenging task. This paper presents the method of solar radiation estimation using support vector machine (SVM). The main objective of this work is to examine the feasibility of SVM and explore its potential in solar radiation estimation. A total of 20 SVM models using different combinations of sunshine ratio, maximum and minimum air temperature, relative humidity, and atmospheric water vapor pressure as input attributes are explored using meteorological data at 15 stations in China. These models significantly outperform the empirical models with an average 14 % higher accuracy. When sunshine duration data are available, model SVM2 using sunshine ratio and air temperature range is proposed. It significantly outperforms the empirical models with an average 26 % higher accuracy. When sunshine duration data are not available, model SVM19 using maximum temperature, minimum temperature and atmospheric water vapor pressure is proposed. It significantly outperforms the temperature-based empirical models with an average of 18 % higher accuracy. The remarkable improvement indicates that the SVM method would be a promising alternative over traditional approaches for estimation of solar radiation at any locations.     

STUDIES ON CLIMATE CHANGE IN CHINA IN RECENT 45 YEARS

Based on the data of monthly mean air temperature and precipitation from about 400 stationsin 1951—1995.and the data of maximum and minimum air temperatures,relative humidity,totalcloud cover and low-cloud cover,sunshine duration,evaporation,wind speed,snow-covered daysand depth,and soil temperatures in 8 layers from 0 m down to 3.2 m from 200 odd stations in 1961—1995.the climate change and its characteristics in China in recent 45 years have been analyzedand studied comprehensively.This paper,as the first part of the work.has analyzed the climatechange and regularities of such meteorological elements as mean air temperature,maximum andminimum air temperatures,precipitation,relative humidity and sunshine duration.The possiblemechanism on climate change in China and the climate change and regularities of othermeteorological elements will be discussed in another paper as the second part.     

Estimation of the monthly and annual mean maximum and mean minimum air temperature values in Greece

In this study, regression equations to estimate the monthly and annual values of the mean maximum and mean minimum air temperatures in Greece are derived. For this purpose, data from 87 meteorological stations distributed all over Greece are used. Geographical parameters, i.e., altitude, latitude, longitude, minimum distance from the sea and an index of terrain morphology, are used as independent variables. These equations explain 79?C97% of the variance of the temperature values and have standard error of estimate between 0.59 and 1.20°C. Data from 37 other meteorological stations are used to validate the accuracy of the equations. Topographic or climatic factors, which could not be introduced into the equations, are responsible for most temperature residuals >0.5°C or <?0.5°C. Moreover, some particular emphasis has been given to the values of the regression coefficient for the altitude, since it is the estimator for the mean lapse rate of air temperature.     

深圳市流感就诊率季节特征及夏季流感就诊率气象预报模型

利用深圳市2003-2007年5年的流感样病例资料和同期气象资料,对深圳市夏季流感与气象条件的关系进行了分析与统计。研究发现深圳市流感高峰期发生在春季和夏季,且存在向夏季转移的趋势,这种流感流行的季节差异与天气条件有很大的关系,受气温、相对湿度的影响显著,在平均气温处于25-30℃之间,相对湿度较高的天气条件下易出现流感高峰。用最低气温、最小相对湿度和日照时数为预报因子,建立了深圳市夏季流感就诊率的等级预报模型。     

Assessment of Air Temperature Trends in the Source Region of Yellow River and Its Sub-Basins,China

Changes in climatic variables at the sub-basins scale (having different features of land cover) are crucial for planning, development and designing of water resources infrastructure in the context of climate change. Accordingly, to explore the features of climate changes in sub-basins of the Source Region of Yellow River (SRYR), absolute changes and trends of temperature variables, maximum temperature (Tmax), minimum temperature (Tmin), mean temperature (Tavg) and diurnal temperature range (DTR), were analyzed annually and seasonally by using daily observed air temperature dataset from 1965 to 2014. Results showed that annual Tmax, Tmin and Tavg for the SRYR were experiencing warming trends respectively at the rate of 0.28, 0.36 and 0.31°C (10 yr)^?1. In comparison with the 1st period (1965-1989), more absolute changes and trends towards increasing were observed during the 2nd period (1990-2014). Apart from Tangnaihai (a low altitude sub-basin), these increasing trends and changes seemed more significant in other basins with highest magnitude during winter. Among sub-basins the increasing trends were more dominant in Huangheyan compared to other sub-basins. The largest increase magnitude of Tmin, 1.24 and 1.18°C (10 yr)^?1, occurred in high altitude sub-basins Jimai and Huangheyan, respectively, while the smallest increase magnitude of 0.23°C (10 yr)^?1 occurred in a low altitude sub-basin Tangnaihai. The high elevation difference in Tangnaihai probably was the main reason for the less increase in the magnitude of Tmin. In the last decade, smaller magnitude of trend for all temperature variables signified the signal of cooling in the region. Overall, changes of temperature variables had significant spatial and seasonal variations. It implies that seasonal variations of runoff might be greater or different for each sub-basin.     

Agrometeorological study of crop drought vulnerability and avoidance in northeast of Iran

Drought is one of the crucial environmental factors affecting crop production. Synchronizing crop phenology with expected or predicted seasonal soil moisture supply is an effective approach to avoid drought impact. To assess the potential for drought avoidance, this study investigated the long-term climate data of four locations (Bojnourd, Mashhad, Sabzevar, and Torbat Heydarieh) in Khorasan province, in the northeast of Iran, with respect to the four dominant crops (common bean, lentil, peanut, and potato). Weekly water deficit defined as the difference between weekly precipitation and weekly potential evapotranspiration was calculated. Whenever the weekly water deficit was larger than the critical water demand of a crop, the probability for drought was determined. Results showed that Sabzevar has the highest average maximum temperature (24.6 °C), minimum temperature (11.7 °C), weekly evapotranspiration (32.1 mm), and weekly water deficit (28.3 mm) and has the lowest average weekly precipitation (3.8 mm). However, the lowest mean maximum temperature (19.7 °C), minimum temperature (6.9 °C), weekly evapotranspiration (22.5 mm), and weekly water deficit (17.5 mm) occur in Bojnourd. This location shows the shortest period of water deficit during the growing season for all crops except potato, which also experienced drought at the end of the growing season. Sabzevar and Torbat Heydarieh experienced the highest probability of occurrence and longest duration of drought during the growing season for all crops. The result of this study will be helpful for farmers in order to reduce drought impact and enable them to match crop phenology with periods during the growing season when water supply is more abundant.     

Selective inverted sink efficiency for spring frost protection in almond orchards northwest of Isfahan, Iran

A so-called selective inverted sink (SIS) was validated in frost protection of a 20-ha almond orchard. Daily counts of flower buds were made for two branches of some selected almond trees in every plot to determine frost damage percentage. Temperatures increased due to the SIS system, but there was an average gradient of temperature decrease of about 0.4°C per 100?m with distance from the SIS. The minimum air temperature increased from 0.5 to 2.8°C, with the highest increase closest to the SIS. The percent of frost-damaged flower buds of almond relative to the control plot with distance to the SIS system had its maximum gradient (8% per 100?m ) in 100?C200-m distance from the SIS, but this gradient decreased to a minimum (4% per 100?m) in 500?C700-m distance from the SIS. The ANOVA and Duncan??s multiple-range test of air temperature and frost damage data confirm that the significant influence zone of this local SIS was about 500?m.     

新疆近50,a气候的变化特征

利用新疆地区具有较好代表性的23个气象台站1960-2009年的历史气候资料,运用线性倾向估计对新疆地区近50 a来气候变化的主要特征进行了分析.结果表明：近50 a来,新疆地区能量供给因子中的最高、最低和平均温度都呈明显的上升趋势,而日照时数、温度年较差呈明显的下降趋势,云量的变化趋势不明显并略有下降;空气动力因子风速的下降趋势显著;湿度因子中空气相对湿度和降水量略有上升趋势,而水汽压有明显上升趋势.受此影响,近50 a新疆地区气候总体趋于干向湿发展的趋势,气候朝暖湿方向变化.     

ANNUAL VARIATIONS OF TEMPERATURE ON FOUR URBAN UNDERLYING SURFACES AND FITTING ANALYSIS

Based on the observed 2-year temperature data for four kinds of typical urban underlying surfaces, including asphalt, cement, bare land and grass land, the annual variations and influencing factors of land surface temperature are analyzed. Then fitting equations for surface temperature are established. It is shown that the annual variation of daily average, maximum and minimum temperature and daily temperature range on the four urban underlying surfaces is consistent with the change in air temperature. The difference of temperature on different underlying surfaces in the summer half year (May to October) is much more evident than that in the winter half year (December to the following April). The daily average and maximum temperatures of asphalt, cement, bare land and grass land are higher than air temperature due to the atmospheric heating in the daytime, with that of asphalt being the highest, followed in turn by cement, bare land and grass land. Moreover, the daily average, maximum and minimum temperature on the four urban underlying surfaces are strongly impacted by total cloud amount, daily average relative humidity and sunshine hours. The land surface can be cooled (warmed) by increased total cloud amount (relative humidity). The changes in temperature on bare land and grass land are influenced by both the total cloud amount and the daily average relative humidity. The temperature parameters of the four land surfaces are significantly correlated with daily average, maximum and minimum temperature, sunshine hours, daily average relative humidity and total cloud amount, respectively. The analysis also indicates that the range of fitting parameter of a linear regression equation between the surface temperature of the four kinds of typical land surface and the air temperature is from 0.809 to 0.971, passing the F-test with a confidence level of 0.99.     

黑龙江省草地螟第三暴发周期气候特征及风险概率

1996年以来黑龙江省草地螟第三暴发周期持续至今,危害日益加重。以1959-2008年黑龙江省28个国家基本站的气象资料以及草地螟暴发期等资料为基础,分析了黑龙江省草地第三暴发周期的气候特征及风险概率。结果表明：近50 a来,黑龙江省年平均气温、年平均最低气温呈显著的上升趋势,通过0.001显著性检验,气温在1988年前后出现突变。其它要素,如降水量、降水日数、风速、日照时数均呈减少趋势,但只有年日照时数和年平均风速的减少趋势通过了显著性检验。哈尔滨草地螟始发日期与同期平均气温、日最高气温、最低气温、最小相对湿度关系密切,应该是本地越冬虫源春季羽化对气温、相对湿度敏感性较高;同时始见日期与最大风速的风向相关较为密切,可能是由于外地虫源对风向敏感性较高。通过对黑龙江省草地螟高峰期首日的风险概率分析,得到黑龙江省草地螟高峰期出现在5月最后一个候的风险概率为23.6%;出现在6月上旬的风险概率为36.6%;出现在6月中旬的风险概率为24%;出现在6月下旬的风险概率为14.4%。     

The effect of air temperature and human thermal indices on mortality in Athens, Greece

This paper investigates whether there is any association between the daily mortality for the wider region of Athens, Greece and the thermal conditions, for the 10-year period 1992–2001. The daily mortality datasets were acquired from the Hellenic Statistical Service and the daily meteorological datasets, concerning daily maximum and minimum air temperature, from the Hellinikon/Athens meteorological station, established at the headquarters of the Greek Meteorological Service. Besides, the daily values of the thermal indices Physiologically Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) were evaluated in order to interpret the grade of physiological stress. The first step was the application of Pearson’s χ ² test to the compiled contingency tables, resulting in that the probability of independence is zero (p?=?0.000); namely, mortality is in close relation to the air temperature and PET/UTCI. Furthermore, the findings extracted by the generalized linear models showed that, statistically significant relationships (p?<?0.01) between air temperature, PET, UTCI and mortality exist on the same day. More concretely, on one hand during the cold period (October–March), a 10°C decrease in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 13%, 15%, 2%, 7% and 6% of the probability having a death, respectively. On the other hand, during the warm period (April–September), a 10°C increase in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 3%, 1%, 10%, 3% and 5% of the probability having a death, respectively. Taking into consideration the time lag effect of the examined parameters on mortality, it was found that significant effects of 3-day lag during the cold period appears against 1-day lag during the warm period. In spite of the general aspect that cold conditions seem to be favourable factors for daily mortality, the air temperature and PET/UTCI exceedances over specific thresholds depending on the distribution reveal that, very hot conditions are risk factors for the daily mortality.     

Quantifying the effects of climate trends in the past 43 years (1961–2003) on crop growth and water demand in the North China Plain

This paper explores changes in climatic variables, including solar radiation, rainfall, fraction of diffuse radiation (FDR) and temperature, during wheat season (October to May) and maize season (June to September) from 1961 to 2003 at four sites in the North China Plain (NCP), and then evaluates the effects of these changes on crop growth processes, productivity and water demand by using the Agricultural Production Systems Simulator. A significant decline in radiation and rainfall was detected during the 43 years, while both temperature and FDR exhibit an increasing trend in both wheat and maize seasons. The average trend of each climatic variable for each crop season from the four sites is that radiation decreased by 13.2 and 6.2 MJ m^?2 a^?1, precipitation decreased by 0.1 and 1.8 mm a^?1, minimum temperature increased by 0.05 and 0.02°C a^?1, maximum temperature increased by 0.03 and 0.01°C a^?1, FDR increased by 0.21 and 0.38% a^?1 during wheat and maize season, respectively. Simulated crop water demand and potential yield was significantly decreased because of the declining trend in solar radiation. On average, crop water demand was decreased by 2.3 mm a^?1 for wheat and 1.8 mm a^?1 for maize if changes in crop variety were not considered. Simulated potential crop yields under fully irrigated condition declined about 45.3 kg ha^?1 a^?1 for wheat and 51.4 kg ha^?1 a^?1 for maize at the northern sites, Beijing and Tianjin. They had no significant changes in the southern sites, Jinan and Zhengzhou. Irrigation, fertilization development and crop variety improvement are main factors to contribute to the increase in actual crop yield for the wheat–maize double cropping system, contrasted to the decline in the potential crop yield. Further research on how the improvement in crop varieties and management practices can counteract the impact of climatic change may provide insight into the future sustainability of wheat–maize double crop rotations in the NCP.